function []= test()

xn=[0,1,2,3,4,5,6,7];

n=0:length(xn)-1;
xk=fft(xn);
x=ifft(xk);
subplot(3,1,1);stem(n,xn,'h','fill');title('xn');

subplot(3,1,2);stem(n,abs(xk),'h','fill');title('DFT');
subplot(3,1,3);stem(n,x,'h','fill');title('IDFT');
end
